Directional control of earth boring apparatus

ABSTRACT

Apparatus for exercising directional control over earth boring equipment wherein means which may be periodically caused to engage the wall of the bore hole are provided. The bore wall engaging means are carried by an auger head and will engage the bore wall during a portion of each revolution of the boring apparatus when energized. The arc of the circle along which the bore wall engaging means will be extended from the auger head may be selectively adjusted to thereby permit the compensation for undesired borehole drift in any direction.

United States Patent 13,554302 T [72] Inventors David E. Adkins; 2,797,065 6/1957 Houstonl 175/272 Donald J. l-lackman, Columbus, Ohio 2,841,380 7/1958 Thassy l75/267X [2]] Appl. No. 742,798 3,243,001 3/1966 Vincent... 175/33 [22] Filed July 5, 1968 3,356,167 12/1967 Trent l7S/267X Patented Jan. 12,1971 2,923,537 2/1960 Wilcox 175/91X [73] Assignee American Gas Association, In 3,459,453 8/1969 Brill et al. 299/59 New Primary ExaminerMarvin A. Champion a corporauon of New York Assistant Examiner-Richard E. Favreau Attorney-Fishman and Van Kirk [54] DIRECTIONAL CONTROL OF EARTH BORING APPARATUS 11 Claims, 4 Drawing Figs. [52] US. Cl. 175/26, ABSTRACT; Apparatus f exercising directional comm] 173/80, 175/73, l75/267 over earth boring equipment wherein means which may be [51] lnLCl E2lh 7/04 periodically caused to engage the n f the bore hole are Field of Search l/73,6l, provided The bore n engaging means are carried by an 26612637272. 81, 91; auger head and will engage the bore wall during a portion of 7299/59, each revolution of the boring apparatus when energized. The arc of the circle along which the bore wall enga in means will [56] References cued be extended from the auger head may be selec tiv ly adjusted UNITED'STATES PATENTS to thereby permit the compensation for undesired borehole 2,316,409 4/1943 Downing /73 drift in any direction.

DIRECTIONAL CONTROL OF EARTH BORING APPARATUS BACKGROUND OF THE INVENTION:

1. Field of the Invention 1 I The present invention relates to earth boring. More particularly,=the present in .ntion relates to the directional control of horizontal earth boring tools. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character. I

2. Description of the Prior Art j Utility companies have long recognized the costly labor expense and public opposition associated with the prior art horizontal angering has in recent years been specified in many situations requiring the placement of utility. lines under roads and railroads. p

Prior art horizontal augering equipment however, been plagued with a serious problem. This problem resides in the previously. existing. inability to exercise control over the direction of the drill string so that the drill may be redirected should it deviate from the correct drilling'path. As is known, unpredictable drift in underground boring operations is caused by the flexibilityof'the boring tool. It is extremely difficult to make such tools stiff or rigid enough to withstand lateral thrust loads imposed on the drill head or bit by stone, other soil discontinuities, or even by the rotational torque transmitted to the drill string from the. driving apparatus.

The above-noted deflectionor drift phenomenon has been most pronounced when the ratio of drill string length to drill string diameter becomes large. In addition,since"tlie location of the boring bit is not always readily apparent,the drill string may drift as much as 6 feet in 100 feet or more before being noticed and corrective measures attempted.

In the prior art, the only directional control available is the use of pickup, or potholeslocated at intervals along the desired tunnel path, the bit being realigned-if necessary as it passes .each of the pickup holes. This technique is, however, only effective when. bores are .attem pted without'a casing and many times drill string deflection between-pick upjpickup holes or too slight to be visually noticed atpickupholes will make it difficult to later insert a casingor carrier pipe. Also, the use of pickup holes is subject to the same public opposition, albeit to a lesser degree, as trenching. k L

It has been recognized that a more accurate method for underg'round installation of a conduitlencompass'es augering through a casing while simultaneously jacking the :casing.

However, this method will also fail {when the drill string is SUMMAR-YOF Tl-IE'INVENTION' an auger mounted cam. The auger cam rotates with the auger and thus, through the control valve, causes selective energization of the piston actuated radial bit. When energized, the bit extends out the side of the auger head and reams a swath from the side of the borehole in the direction that needs correction.

BRIEF DESCRIPTION OF THE DRAWING The present invention may be better understood and its nu merous advantages will become readily apparent to those skilled in the art by reference to the accompanying drawing wherein like reference numerals refer to like elements in the various FIGS. and in which:

FIG. 1 is a side elevation view of a preferred embodiment of the present invention.

FIG. 2 is an enlarged view, partially in section, of the radial cutter portion of the embodiment of HO. 1.

FIG. 3 is a front view of the apparatus shown in F IG. 2.

FIG. 4 is a front view of a modifiedembodim'ent of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, the selective cutter system of the present invention comprises a piston actuated, radial earth reaming bit, indicated generally at 10,- which is positioned 7 within the head assembly 12 of an auger, indicated generally at 14. The selective cutter also comprises, as principal components, a hydraulic fluid system and an auger cam 16 which controls the application of fluid pressure and flow to radial bit 10 from the hydraulic fluid systemin the manner to be described below.

The auger head 12, as may best be seen from a simultaneous consideration of FIGS. 2 and 3, comprisesa hollow, substantially rectangular casing 18 which has,extending from its front face, a plurality of cutter teeth 20. The auger head assembly also comprises a pilot bit 22 which extends in a forward direction axially of the auger. v

The auger has a tubular support shaft 38, hereinafter referred to as the auger pipe, which is supported at the end opposite to head assembly 12 by means of a pair of bearings 24 and 26. Torque is transmitted to the auger, via a drive 1 coupling 28, by means of a sprocket 30 and chain drive. The

details of drive coupling 28 do not comprise part of the present invention and thus have been omitted from the drawing in theinterest of clarity. However, drive coupling 28 is comprised of a male octagonal member fitting into a female octagonal member fitted with a shear screw to prohibit axial motion, the center of the connection being hollow and of the same inside diameter as the auger pipe 38.

Bearings 24 and 26 are mounted on a sliding frame 32 and thus, upon disconnecting of the drive coupling 28, the bearings may be moved axially of the auger. Accordingly, as the bore progresses, additional sections or lengths of auger pipe may be coupled to the equipment to thereby extend the hole. Also in the interest of clarity, the drive chain and driving mechanism for sprocket 30 have not-been shown. These elements would either be mounted on slidable frame 32 or elsewhere and would move with frame 32. The means for moving frame32 and thus the means for urging theauger forward will consist of the force from'a large'hydraulic cylinder, not

The present invention overcomes the above-discussed disadvantages of the prior art and, in sodoiri'gyprovides for the redirection-of a horizontalaugering tool when-it 'ilrifts or is shown, rigidlyattached to the sliding frame 32. The cylinder exerts its forceagainst the track upon which the frame's'lides thereby pushing the frame'and the auger apparatus forward with respect to the stationary track.

It is to be noted that a pair of hydrauliclines 34 and 36 extend rearwardly from head assembly 12. Hydraulic lines 34 and 36 will be external to auger pipe 38 only until they pass an instrumented section 39 thereof. Auger section 39 will contain suitable sensors for detecting the direction of motion of the auger. These sensors do not form a part of thepresent invention and will not be described herein. However, it is to be noted that the sensors in the instrumented auger section will detect undesired drift-ofthe auger'and will provide signals commensurate therewith. The signals commensurate with drift may either be applied to suitable indicators so as to enable the exercise of manual control over the operation of head assembly 12 or the drift signals may be employed to automatically control the hydraulic system of the present invention to thereby cause proper corrective action. Once past instrumented auger pipe section 39, hydraulic lines 34 and 36 proceed rearwardly iiside the auger pipe for the remainder of the auger length. A hollow, octagonal, mechanical auger connection, similar to the apparatus described above in connection with the discussion of drive coupling 28, will permit coupling of succeeding auger pipe sections. Internally of each of these mechanical connections will be a pair of quickdisconnect couplings for hydraulic lines 34 and 36, the hydraulic lines passing through the center of the auger pipe connections. Thus, as shown in FIGS. 1 and 2, hydraulic lines 34 and 36 are partly exterior of and partly interior of auger pipe 38. It is to be noted, however, that the hydraulic lines may be totally interior of auger pipe 38 if the passing of the hydraulic lines through the instrumented section of the auger pipe is deemed necessary in the interest of protection. The hydraulic lines will rotate with the auger, such rotation being facilitated in the manner to be described below.

The hydraulic lines 34 and 36 exit from auger pipe 38 through the center of auger cam 16 which is fixed to the rotating pipe. The hydraulic lines thereafter pass through a rotary hydraulic joint, indicated generally at 40. Rotary hydraulic joint 40 is used to transmit two-way separate hydraulic flow and converts this flow from lines rotating with the auger to stationary lines. After passing through the rotary hydraulic joint, the fluid supply lines will be connected to a four-way hydraulic spool valve 42. Fluid is supplied to the control system including valve 42 from a pressurized fluid source 44 via hydraulic lines 46 and 48.

Considering now F lGS. 2 and 3, the structure of the auger head and piston actuated, radial selective earth reaming bit may be more clearly seen. Radial bit comprises a cutter element 50 which engages an extension of piston rod 52 of a piston 54. The auger head casing 18 has a first recess 56 machined in one end thereof, recess 56 being commensurate in shape with the outer diameter of the cutter element 50. Accordingly, by proper application of hydraulic pressure to piston 54 in the manner to be described below, cutter element 50 may be retracted to a point where it does not extend beyond the sidewalls of the auger head.

The piston 54 travels within a cylinder 58 which is machined in casing 18, the cylinder extending from the end opposite to that having the cutter element receiving recess 56. The outwardly disposed end of cylinder 58 is capped by a plug 60 which threadably engages the inner wall of the cylinder.

The auger head casing 18 also comprises an extension 62 which fits into tubular auger support shaft 38. Mating of the auger head with the shaft 38 may be achieved via a bayonettype connection, not shown. Auger head extension 62 is provided with a pair of bores 64 and 66 which respectively communicate between the inner and outer ends of cylinder 58 and the interior of shaft 38. Flexible extensions 68 and 70 respectively of hydraulic lines 34 and 36 may be coupled via suitable fitting, not shown, to the exposed ends of bores 64 and 66 in auger head extension 62.

The operation of the above-described equipment will now be explained. Under normal circumstances, valve 42 is supported by means, not shown, in a position where its operating shaft 72 is out of contact with auger cam 16. When deviation of the auger from its desired path is noticed, such deviation being sensed by apparatus which does not comprise part of the present invention, the valve shaft is moved into contact with the auger cam. The auger cam 16 is fixed to the rotating auger shaft 38 and aligned with the cutter bit 50. As the auger shaft and thus the cam 16 rotates, fluid flow passages through fourway spool valve 42, which will at this time have its operating shaft 72 spring loaded against the auger cam, will be selectively opened. Accordingly, when auger deflection is noticed, the

valve is physically rotated to the proper point and moved into a position where its spool engages the auger cam 16 via shaft 72. Pressurized hydraulic fluid from source 44, which may be the central hydraulic system of the boring machine which may provide rotary drive to the auger or linear force via the large pushing cylinder to the sliding frame, will thus be fed through valve 42, rotary hydraulic joint 40 and, via fluid supply lines 34 and 36 to piston cylinder 58. Restated, pressurized fluid will be fed forward to the selective piston when a forward valve port in spool valve 42 is opened by the high point on the auger cam 16. In one case where the pressure at source 44 was approximately 2,000 p.s.i., the cutter piston 54 was energized with approximately 5,000 pounds of force upon the opening of the forward valve port. When the forward or head side of piston 54 is subjected to pressure, the cutter bit extends out the side of the auger head 12, as shown in FIGS. l3, approximately three-quarters of an inch and will ream a 90 swath from the side of the bore hole in the direction that needs correction. When the valve spool of valve 42 follows the low side of auger cam 16, the reverse side of piston 54 will be pressurized and the forward or outer side ofpiston 54 bled back to the reservoir in source 44 thus forcing the cutter bit 50 back into the auger head for the remainder of the auger revolution. Therefore, the borehole is reamed only in one quadrant while the forward progress of the bore continues without interruption.

It is to be noted that the present invention has been shown and described in the environment wherein boring is performed without a casing. In the usual instance of drilling without a casing, the apparatus of the present invention would be employed to drill a pilot hole which would thereafter be enlarged if necessary. It is, however, to be understood that the present invention could be employed where the auger extends through a casing which is fed into the bore as it is extended.

It is also to be noted that, while manual positioning of valve 42 relative to auger cam 16 has been described, the present invention can and typically would be automated to the extent possible, the extension of the auger being the sole nonautomatable task. Thus, signals from a suitable direction sensitive device may be fed to a logic circuit which, in turn, would actuate a servomotor. The motor would be employed to rotate valve 42 until it is positioned properly relative to the cam to provide the necessary corrective cutting.

While a preferred embodiment of the present invention has been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the present invention. For example. while a selective cutter has been described, cutter bit 50 could be replaced by a wedge. In FIG. 4, for example, a wedge pivotally mounted on casing 18' at 82 is actuated by the piston rod 52 being connected thereto by the pin and slot arrangement 84. Upon actuation of the piston, the wedge is moved outwardly for example to a position 86 as shown in broken lines during a portion of each revolution of the bit. The effect of a wedge that selectively pushes against the sidewall of a borehole would be equal and opposite to the cutting effect. The wedge, pushing once on the wall for each auger revolution, would tend to walk" the auger back on the correct path. Obviously, for wedge operation, the wedge would be caused to push on the wall opposite to the direction needing correction. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.

We claim:

1. Directionally controllable earth boring apparatus comprising:

an elongated rotatable auger;

an auger head mounted adjacent a first end of said auger for rotation therewith;

retractable bore wall engaging means mounted in said auger head, said retractable means in the normal retracted position lying in flush relation with said auger head. said retractable means being movable in a direction generally transverse to the longitudinal axis of said auger; and

selectively energizable control means for causing said wall engaging means to extend from said auger head andengage the bore wall during a selective portion of each auger revolution. V f 2. The apparatus of claim 1 wherein said control means is controllable from a point remote from'said auger head.

3. The apparatu" of claiml wherein said control means comprises:

angular position indicating means mounted on and rotating with said auger; and means responsive to said angular position indicating means for generating control signals for said retractable means. 4. The apparatus of claim 3 wherein said auger head includes a cylinder and wherein said retractable means com- P a fluid-operated. piston, said piston being movable within said auger head cylinder; and bore wall engaging meansoperatively connected to said piston. m 5. The apparatus of claim 4 wherein said control signal generating means comprises;

valve means operated by means; a source of pressurized fluid; means connecting said fluid source to said valve means; and means connecting said valve means tosaid auger head cylinder whereby operation of said valve by said rotating angular position indicating means results in periodic extension and retraction of said bore wall-engaging means. 6. The apparatus of claim 5 wherein said valve means and said angular position indicating means are adjustably positionable relative to one another whereby extension of said bore wall engaging means along a preselected arc of the circle said angular position indicating transcribed by said rotating auger may be obtained.

7. The apparatus of claim 6 wherein said angular position indicating means comprises a cam mounted on said auger for rotation therewith. Y

8. The apparatus of claim 7 wherein said value means comprises:

a hydraulic valve; and

adjustable support means for said valve. said support means enabling the position of said valve means to be angularly adjusted relative to said auger cam and enabling said valve means to be moved into operative relationship with said cam when directional control of said auger is to be effected.

9. The apparatus of claim 7 wherein said wall engaging means comprises a cutter blade.

10. The apparatus of claim 7 wherein said wall engaging means comprises a wedge.

11. Directionally controllable earth boring apparatus comprising:

an elongated rotatable auger;

an auger head mounted adjacent a first end of said auger for rotation therewith;

retractable bore wall engaging means mounted in said auger head, said retractable means being movable in a direction generally transverse to the longitudinal axis of said auger;

sensing means for sensing a deviation of said auger from a predetermined path; and

control means responsive to said sensing means for causing said wall engaging means to extend from said auger head and engage the bore wall during a selective portion of each auger revolution to correct auger path deviations. 

1. Directionally controllable earth boring apparatus comprising: an elongated rotatable auger; an auger head mounted adjacent a first end of said auger for rotation therewith; retractable bore wall engaging means mounted in said auger head, said retractable means in the normal retracted position lying in flush relation with said auger head, said retractable means being movable in a direction generally transverse to the longitudinal axis of said auger; and selectively energizable control means for causing said wall engaging means to extend from said auger head and engage the bore wall during a selective portion of each auger revolution.
 2. The apparatus of claim 1 wherein said control means is controllable from a point remote from said auger head.
 3. The apparatus of claim 1 wherein said control means comprises: angular position indicating means mounted on and rotating with said auger; and means responsive to said angular position indicating means for generating control signals for said retractable means.
 4. The apparatus of claim 3 wherein said auger head includes a cylinder and wherein said retractable means comprises; a fluid-operated piston, said piston being movable within said auger head cylinder; and bore wall engaging means operatively connected to said piston.
 5. The apparatus of claim 4 wherein said control signal generating means comprises: valve means operated by said angular position indicating means; a source of pressurized fluid; means connecting said fluid source to said valve means; and means connecting said valve means to said auger head cylinder whereby operation of said valve by said rotating angular position indicating means results in periodic extension and retraction of said bore wall engaging means.
 6. The apparatus of claim 5 wherein said valve means and said angular position indicating means are adjustably positionable relative to one another whereby extension of said bore wall engaging means along a preselected arc of the circle transcribed by said rotating auger may be obtained.
 7. The apparatus of claim 6 wherein said angular position indicating means comprises a cam mounted on said auger for rotation therewith.
 8. The apparatus of claim 7 wherein said value means comprises: a hydraulic valve; and adjustable support means for said valve, said support means enabling the position of said valve means to be angularly adjusted relative to said auger cam and enabling said valve means to be moved into operative relationship with said cam when diRectional control of said auger is to be effected.
 9. The apparatus of claim 7 wherein said wall engaging means comprises a cutter blade.
 10. The apparatus of claim 7 wherein said wall engaging means comprises a wedge.
 11. Directionally controllable earth boring apparatus comprising: an elongated rotatable auger; an auger head mounted adjacent a first end of said auger for rotation therewith; retractable bore wall engaging means mounted in said auger head, said retractable means being movable in a direction generally transverse to the longitudinal axis of said auger; sensing means for sensing a deviation of said auger from a predetermined path; and control means responsive to said sensing means for causing said wall engaging means to extend from said auger head and engage the bore wall during a selective portion of each auger revolution to correct auger path deviations. 